4x4 slipping?

T

tonybaloney

New member
so i was going along driving straight on a freeway this morning around 30-40mph. it started raining so i switched from h2 to h4 as usual. the 4x4 engaged after 5-7 blinks as usual. except this time, it felt like the something "slipped" a couple of times during the 5-7 blinks. it's very slightly but i still felt/heard it. i changed from h4 to h2 and same thing happened once. i then did it 3 or 4 more times at different speed (all lower than 63mph of course) and couldn't re-produce it anymore. it works fine now. should i be worried?

i was just talking about changing my differential oil at 100k on another thread (http://www.toyota-4runner.org/maintenance/51717-30-k-service-3.html#post515027) so i'm a pretty paranoid person (as my wife would say). so what do you guys think?
 
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I would say that based on the fact that you switch into 4x4 when it starts raining, you are really paranoid.

As far as the slipping when changing drive modes, there is a possibility that the clutches could be slipping inside the t-case. Try changing the t-case fluid a couple times to see if that helps. Each time you change the fluid, after you add the new fluid, drive to an area that you can safely do some tight figure 8's in 4x4. Without the center diff locked in of course.

This usually works in GM t-cases as well.
 
haha thanks for the input. we don't get snow here so might as well use my 4x4 when it rains. it has only happened once so far so we'll see if i experience it again. anyone else has other inputs? should i change out my diff oil right away? thanks!
 
tonybaloney said:
so i was going along driving straight on a freeway this morning around 30-40mph. it started raining so i switched from h2 to h4 as usual. the 4x4 engaged after 5-7 blinks as usual. except this time, it felt like the something "slipped" a couple of times during the 5-7 blinks. it's very slightly but i still felt/heard it. i changed from h4 to h2 and same thing happened once. i then did it 3 or 4 more times at different speed (all lower than 63mph of course) and couldn't re-produce it anymore. it works fine now. should i be worried?

i was just talking about changing my differential oil at 100k on another thread (http://www.toyota-4runner.org/maintenance/51717-30-k-service-3.html#post515027) so i'm a pretty paranoid person (as my wife would say). so what do you guys think?
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Nothing to worry about. Don't go changing fluids unless they are dirty and need it. With the push button 4x4 the system may need to be more "at rest" or have a touch of "slack" for the 4x4 to engauge instantly. You can switch to 4hi while moving no problem, but next time do it, then let off the gas, and I'll be it catched right away. Since you couldn't replicate the "slipping" feeling, you have NOTHING to worry about. Even my old manual 4x4 Tacoma wouldn't release the 4x4 unless I let off the gas. The system needs to be with out load to engauge/disengauge quickly. Be sure to engauge the 4x4 hi and low once a month to keep the motors/actuators working properly. Other than that don't worry about what happened, sounds normal to me!
 
i just got back from test driving it and couldn't reproduce it so i'm not going to worry about it. since i don't tow anything, i haven't service my transfer box yet. might do it during my 70k or 100k service.

for using 4hi in the rainfall, it actually helps a lot especially when you drive on the freeway. ever since i drove my runner, i feel unsafe in my FWD cars. we'll be buying a new car soon and we're thinking about the honda crosstour.
 
since we're on this topic, i have another question. i know we're not supposed to change from 2hi to 4hi or vice verse when we're turning. if you "accidentally" do it (with a bit of weird sound and lags) and just straighten out and the 4hi or 2hi engage right after that, is there any damage done? another way to ask the question is, i know the 4hi/2hi won't engage while cornering but is it possible to damage the system? are there any other ways to damage the system or the system is foolproof? thanks guys!

edit: to answer my own question, the only thing i can think of is locking the center diff while driving on hard surface. anything else?
 
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tonybaloney said:
i see. so can you explain what i felt/heard and should i be worried?
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Sorry, I don't know but I presume it has to do with the V6 mulit-mode setup with which I'm unfamiliar. My guess is if you regularly exercise the system, along with the other parts of the 4WD system, you won't experience any unfamiliar delays. If those things aren't used for a while, they can be a little sticky.
 
Don’t’ feel too bad about throwing it into 4h when it rains. I do the same thing. It’s my reminder during the summer months to keep the 4x4 system lubed when I would otherwise run 2h mostly.
 
nismojason said:
I am the only one that thinks it extremely odd to put it in 4Hi for a common rain fall?
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Not at all. I won't engage 4WD in the snow unless I feel like I'm not in control. People with AWD or who engage 4WD at the hint of slippery conditions will lose what skills they have. Of course, many HAVE no skills so maybe I should shut up and let them engage it... :flamewar:
 
same here. Heavy rain, switch to 4Hi to exercise the system. Not much snow here, more black ice it seems. southern Oregon
 
tonybaloney said:
since we're on this topic, i have another question. i know we're not supposed to change from 2hi to 4hi or vice verse when we're turning. if you "accidentally" do it (with a bit of weird sound and lags) and just straighten out and the 4hi or 2hi engage right after that, is there any damage done? another way to ask the question is, i know the 4hi/2hi won't engage while cornering but is it possible to damage the system? are there any other ways to damage the system or the system is foolproof? thanks guys!

edit: to answer my own question, the only thing i can think of is locking the center diff while driving on hard surface. anything else?
Click to expand...

From 2H to 4H, you're suppose to be under 62mph and going straight. Some times 4WD doesn't engage right away and a slight wiggle in the steering wheel is needed to help line up the gears for engagement. You can go from 4H to 2H at any speeds and appears to have no restrictions.

As you mentioned, I think the only major damage that we can do is making turns on high friction surfaces with the center diff locked.
 
nismojason said:
I am the only one that thinks it extremely odd to put it in 4Hi for a common rain fall?
Click to expand...
It may or may not be 'odd'. I do it too, partly so I exercise the system, more because I like how 'glued down' it feels in 4hi. This 4hi mode is more of a full-time 4wd mode than a part-time 4hi mode like most of the Pathy's and X-Terra's. I think the top-trim Pathy has some similar 4hi mode.

tonybaloney said:
since we're on this topic, i have another question. i know we're not supposed to change from 2hi to 4hi or vice verse when we're turning. if you "accidentally" do it (with a bit of weird sound and lags) and just straighten out and the 4hi or 2hi engage right after that, is there any damage done? another way to ask the question is, i know the 4hi/2hi won't engage while cornering but is it possible to damage the system? are there any other ways to damage the system or the system is foolproof? thanks guys!

edit: to answer my own question, the only thing i can think of is locking the center diff while driving on hard surface. anything else?
Click to expand...

Ok, 2hi to 4hi and back is a very sequential event:

-Driver selects 4hi:
1) The t-case goes from 2hi to 4hi locked and dash lights start flashing.
2) The AAD is signaled to engage and connect the right front axle shaft to the differential.
3) The AAD sends a signal back to the t-case controller saying "mission accomplished", the right axle shaft is connected.
4) The controller signals the t-case to unlock the center diff and we're now happily in 4hi with a steady 4wd indication on the dash.

(All that happens in reverse going back to 2wd.)

What gets it bound up is the fact that during the transition to 4hi the center diff is locked on the dry pavement. Sometimes there's a bit of a delay for the AAD signal to be registered and acted upon. The delay allows the drivetrain to bind a bit just like driving in 4hi locked (because it is driving in 4hi locked). If while transitioning the road is curved and you catch it wrong you can bind the driveline a bit. The thump/clank/pop you felt was that energy being released. In general it won't damage anything.

(I theorize that the delay has to do with the AAD. I think the axle can be locked but not fully. This partially locked state prevents the 'locked' signal from being sent to the controller even though there's a mechanical connection. This allows the drivetrain to run in 4hi locked on dry pavement.)


If the road is too straight the AAD may not get in the correct position to lock the right front axle shaft. This is how, occasionally, you can select 4hi and it just doesn't go. You know, when you have to go back to 2wd and try again. Does that help?
Nuke said:
Not at all. I won't engage 4WD in the snow unless I feel like I'm not in control. People with AWD or who engage 4WD at the hint of slippery conditions will lose what skills they have. Of course, many HAVE no skills so maybe I should shut up and let them engage it... :flamewar:
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:50cal::50cal::50cal: Mr Nuke, cruisin' with your ABS and VSC, your skills must be oh-so-sharp:lmao: :lmao::50cal:





You asked for it:D j/k!!!!!!

I agree... Train like fight, fight like you train. When I feel like "driving" I'll see how far I can get in 2wd, shut-off the VSC and slide in rain a bit etc. It is important to stay practiced.
 
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haha... thanks a lot for the info guys. i like to fully take advantage of the modern technologies. i need them to protect me from all the drivers out there that think they're better than they actually are :D
 
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